1. Field of the Invention
This invention relates generally to an apparatus for driving and dynamically spacing attached devices along a timing chain or belt. The invention specifically relates to an apparatus in which the ratio of movement of three or more chains or belts differentially controls the motion and spacing of a series of attachments, and positively maintains the spacing until the attachments are released from driving engagement with the chain.
2. Description of the Prior Art
Conveyers, packaging equipment, and other mechanical apparatus used in the handling of moving products require accurate spacing of lugs, sealing bars, and other operational attachments. The change in spacing of such devices generally requires long change-over time from one product size to another.
Some equipment allows variable spacing along a belt or chain where the lugs are held moveable on the chain or belt and released by mechanical means. For example, see U.S. Pat. No. 3,340,776. The prior art of attachment spacing also teaches two or more apparatuses to drive the same lug, bar, or attachment, as in the packaging machine and sealing bars of U.S. Pat. No. 4,608,797.
The prior art does not teach the use of three or more chains to permit variable spacing of chain attachments.